1. Field of the Invention
The present invention relates to an ultrasonic endoscope, and more particularly, to an ultrasonic endoscope where a balloon can be mounted on a tip portion of an insertion part to be inserted into a body cavity.
2. Description of the Related Art
In the related art, an ultrasonic endoscope has been used in a medical field. The ultrasonic endoscope includes an imaging element and a plurality of ultrasonic transducers that are integrally disposed at a tip portion of an insertion part to be inserted into a body cavity of a subject. Each of the ultrasonic transducers generates ultrasonic waves toward a portion to be observed in the body cavity and receives ultrasonic echoes (echo signals) reflected by the portion to be observed, and electrical signals (ultrasonic wave-detection signals) corresponding to the received ultrasonic echoes are output to an ultrasonic observation device (ultrasonic processor device). Then, after various kinds of signal processing are performed in the ultrasonic observation device, the electrical signals are displayed on a monitor or the like as an ultrasonic tomographic image.
Since the ultrasonic waves and the echo signals are significantly attenuated in the air, an ultrasonic transmission medium (for example, water, oil, or the like) needs to be interposed between the ultrasonic transducers and the portion to be observed. Thus, a stretchable bag-shaped balloon is mounted on a tip portion of the ultrasonic endoscope, and an ultrasonic transmission medium is injected into the balloon so that the balloon is inflated and is in contact with the portion to be observed. Accordingly, air is excluded from a space between the ultrasonic transducers and the portion to be observed, so that the attenuation of the ultrasonic waves and the echo signals is prevented.
A supply/discharge pipe line (supply/discharge pipe line for a balloon) is inserted into the insertion part of the ultrasonic endoscope in order to supply and discharge an ultrasonic transmission medium into and from the balloon. The supply/discharge pipe line includes a supply/discharge port (tip opening) opening to the tip portion of the insertion part, and an ultrasonic transmission medium is supplied into and discharged from the balloon through the supply/discharge port.
Further, the ultrasonic endoscope is cleaned and sterilized after endoscopy, and the supply/discharge pipe line needs to be brushed. Particularly, since liquid, residue, and the like are likely to enter the supply/discharge pipe line from the supply/discharge port in a case in which endoscopy is performed in a state in which a balloon is not mounted, brushing is necessary.
In the brushing of the supply/discharge pipe line, a cleaning brush is inserted into the supply/discharge pipe line from an operation unit side where an inlet of the supply/discharge pipe line is provided, and an operation for pushing and moving the cleaning brush toward the tip in the supply/discharge pipe line and an operation for drawing a brush portion of the cleaning brush back toward the operation unit are performed.
Since the supply/discharge port opens in a direction perpendicular to the axial direction of the insertion part in the ultrasonic endoscope in the related art, the supply/discharge pipe line provided along the axial direction of the insertion part is connected to the supply/discharge port in a state in which the supply/discharge pipe line is bent at a right angle or is bent obliquely. For this reason, when brushing is performed in the supply/discharge pipe line, the brush portion disposed at the tip of the cleaning brush cannot protrude from the supply/discharge port. Accordingly, there is a problem that liquid, residue, and the like entering the supply/discharge pipe line from the supply/discharge port cannot be sufficiently removed. Furthermore, since the supply/discharge pipe line has a very small diameter φ of about 1.0 mm and a thin cleaning brush is also used, a large bending stress is applied to the cleaning brush at a bent portion of the supply/discharge pipe line when the bending angle of the supply/discharge pipe line is increased. For this reason, there is a case in which the cleaning brush may be subjected to bending damage.
In contrast, in an ultrasonic endoscope disclosed in, for example, JP2009-207758A, a tip surface is formed outside the profile of a tip unit-protruding portion where an ultrasonic observation unit is provided (unevenly thick portion side) and a supply/discharge port (a pipe line opening) of a supply/discharge pipe line (a pipe line for a balloon) is provided on the tip surface. According to this ultrasonic endoscope, since a brush portion of a cleaning brush may easily protrude from the supply/discharge port, liquid, residue, and the like present near the supply/discharge port can be efficiently removed by the cleaning brush. Further, since the pipe line for a balloon is connected to the pipe line opening at a gentle bending angle, bending damage to the cleaning brush can also be prevented.